Speaking to an audience at the US National Press Club in Washington, he said: "Biotechnology companies must understand and respect the role of the arm's length regulator, the farmer and the consumer."
Mr Glickman called for an independent scientific review of his department's procedures for approving biotechnology products. The purpose of the review, he said, would be to "ensure that ... our scientists have the best information and tools to ensure our regulatory capabilities continue to evolve along with advances in the new technology".
The Agriculture Secretary also pledged "to strengthen biotechnology guidelines to ensure we can stay on top of any unforeseen adverse effects after initial market approval". He said he was setting up regional monitoring centres to that end.
Although he was upbeat on the safety and benefits of biotechnology, his mention of "unforeseen adverse effects" was a signal departure for the US administration, which has steered clear of suggesting that biotechnological advances might not be safe.
Mr Glickman was speaking after the World Trade Organisation had announced the penalties that the US would be permitted to levy on the EU in retaliation for its ban on US beef. Far from exulting, he reiterated the need for US regulators and producers to keep each other "at arm's length".